1. Field of the Invention
This invention relates to brake systems for internal combustion engines, and particularly to devices operable to increase back-pressure in an exhaust stream discharged from such engines.
2. State of the Art
It is known to install a flow-restricting valve in an exhaust stream from an internal combustion engine to resist high rpm operation of that engine, with the valve essentially acting as a brake for the vehicle. Such valves can provide an open position for unrestricted engine operation, for example to drive the vehicle up a hill, or across level terrain. A closed, or exhaust restricting, position is used as, or to augment, the vehicle's mechanical brakes, such as when driving down an incline.
Certain United States patents document the considerable work that has been done to develop various devices operable to augment mechanical brakes for vehicles. Representative recent patents include: U.S. Pat. No. 6,305,349 to Harris, for “Sliding gate exhaust brake assembly”; U.S. Pat. No. 6,257,201 to Kajiiura et al. for “Exhaust brake”; U.S. Pat. No. 6,205,975 to Ruedin et al. for “Method and apparatus for controlling the actuation of a compression brake”; U.S. Pat. No. 6,152,853 to Banks, III for “Vehicle exhaust brake and control system”; and U.S. Pat. No. 6,062,025 to Okada et al. for “Auxiliary brake system”.
It would be an advance to provide an engine exhaust break arrangement that is reliable, less complicated, and lower-cost to manufacture.